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A145292
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Composite numbers generated by the Euler polynomial x^2 + x + 41.
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17
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1681, 1763, 2021, 2491, 3233, 4331, 5893, 6683, 6847, 7181, 7697, 8051, 8413, 9353, 10547, 10961, 12031, 13847, 14803, 15047, 15293, 16043, 16297, 17071, 18673, 19223, 19781, 20633, 21797, 24221, 25481, 26123, 26447, 26773, 27101, 29111
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OFFSET
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1,1
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COMMENTS
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The Euler polynomial x^2 + x + 41 gives primes for consecutive x from 0 to 39.
For numbers x for which x^2 + x + 41 is not prime see A007634.
Let P(x)=x^2 + x + 41. In view of identity P(x+P(x))=P(x)*P(x+1), all values of P(x+P(x)) are in the sequence. - Vladimir Shevelev, Jul 16 2012
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LINKS
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FORMULA
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MATHEMATICA
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a = {}; Do[If[PrimeQ[x^2 + x + 41], null, AppendTo[a, x^2 + x + 41]], {x, 0, 500}]; a
Select[Table[x^2+x+41, {x, 200}], CompositeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 21 2018 *)
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PROG
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(Haskell)
a145292 n = a145292_list !! (n-1)
a145292_list = filter ((== 0) . a010051) a202018_list
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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